Improvement in arivlillary spheres



2 Sheets--Sheet 1.

H. BRYANT. Improvement in Armillary Spheres.

Patented Sep.10, 1872.

fnl/e2? for:

23h t--sh t2. H. BRYANT. e@ s e@ l Improvement in Armllary Spheres. NQ. 131,148. Patented Sep. 10, 1872.

. mina'.

^ 'rares TE T HENRY BRYANT, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE BRYANT CELESTIAL INDICATOR COMPANY, OF SAME PLACE.

IMPRGVEMENT IN ARMILLARV SPHERES.

Specification forming part of Letters Patent-N0. ESLIIS, dated September 10, 1872.

SPECIFICATION.

I, HENRY BRYANT, of Hartford, in the county of Hartford and State of Connecticut, have invented an Improved Celestial Indicator, of which the following is a specification:

Nature and Objects of the Invention.

My invention is an instrument for use in schools, colleges, and the like, for illustrating and explaining various celestial phenomena, such as are commonly the subject of study and investigation in pursuing the study of astronomy.

Description of the Accompanying Drawing. Figure l is an elevation, which I term, for

convenience sake, a front elevation. Fig. 2

is an elevation, which I term a side elevation, the observer being faced at a right angle to n his position, as indicated in Fig. l. Fig. 3 is a detached sectional view of a portion of the apparatus, representingthe solar system. Fig. 4 is a detached View of the apparatus, whose ofce it is to keep the axis of the earth at all times parallel to the axis of the heavens. Fig. 5 is a detached view ofthe reverse side of the part of the apparatus shown in Fig. 4, and the office of this figure is to show a device for continuing a rotary motion past the two points commonly known as dead-centers.

General Dcscwlltiooz.

The letters a and b indicate two rings or circles of thin sheet metal, crossing each other at right angles, and fastened together at the points of intersection. c isa third ring. whose plane is at a right angle to the planes of both the otherrings, and fastened to them at the `points of intersection. A quarter oi' this ring,

cension, b, meanwhile, representing the first meridian of the heavens. There is a movable meridian, f, pivoted at c5 and c6, which can be swung around the whole sphere, except past the foot d, and, as it is properly graduated, declination can be read off upon it at sight 5 and by bringing it to cover any particular spot on the sphere the declination and right ascension can be readily read ot'f at sight. The ball g in the center represents the sun; h h, the axis of the same. i is the axis of the ecliptic; 7c lc, seen in dotted lines in Fig. 2, through the rst meridian b-the axis of the heavens. All of these axes are attached together at the proper angle of variation to each other, and the axes of the sun and of the heavens turn about the pole of the ecliptic, represented as at i 'i'. The letter l indicates the earth, about which the moon m revolves. The other planets are indicated by the letters 0 o1 o2 o3 o4 o5 o, which are attached by the wires n, of proper lengths to show their relative distances from the sun, to disks s, which are capable of being revolved upon the axis p by an arrangement which will be more particularly described hereinafter. The wire-ring r represents the moons path around the sun, and the shape of the whole ring is such, and it is so placed upon its supports r1 1'1, as to show the eccentricities of its pat-h. Attached to this ring r are two flat plates of metal, r2 r2, to representthe moons nodes, and so engraved as to show where the paths of the earth and moon about the sun intercept eachother. The broad metal band t represents the Zodiac properly inclined to the plane ofthe celestial equator 5 on the middle oftheinside is markedtheline u to represent the ecliptic, and properly divided to show the signs. The circle o represents the path described by the revolution ofthe axis of the heavens about the axis of the ecliptic, and is divided into degrees for the ready measurement of this movement. The wire-ring e, already spoken of, which represen ts the celestial equator, is crossed at right angles by the wire-ring te, which represents a meridian, and the two are fastened together at the points of intersection, which points of intersection represent the equinoxes. The wirering w is fastened to the axis of the heavens at the points where it intersects such axis; and when the pole of the'heavens, which is now at c2, is revolved to the right or West- 2 famine ward, the equinoxes will be seen to fall back on the eeliptic, so as to illustrate and explain the precession of the equinoxes. This motion also illustratesthe movement of the equator of the heavens, thus changing the declination of the stars.

I will now explain the parts which are more particularly shown in Figs. 3, 4, and 5. The axis p is fastened rigidly into the sockets h h. The disk is rigidly fastened to the shaft p, and has a shoulder upon which the disk s', which supports the moons nodes, turns. The other disks turn upon the shaft p. The letter z indicates a nut inclosing the shaft 1J, and turning upon it with a screw-thread, al, for turning the nut up against the disks and fastening them in place. This nut has a milled surface at z2 for the thumb and iin ger, by which it can be turned. Upon the opposite end of the shaft p is the thumb-piece y, operating similarly to the nut z, except that it has no screw-thread, and does not act as a tightener. Upon the side of the disk x, which is toward the thumb-piece y, are two cams, al and a2, the

former overlying` the latter, both equidistant from the center of the disk x, and upon exactly-opposite sides of the center. A collar, b1, which is a part of the arm c1, surrounds the cam al, and a collar, b2, which is a part of the arm c2, surrounds the cam a2. Thesearms el c2 lie in a slot in the disk part of the thumbpiece y, and, as the thumb-piece is revolved, the arms c1 c2 are carried with it, and the cffect of their attachment to the cams al a2 is such as to cause them to work out and in, alternately. Of course, at two points in each revolution the arms will (supposing them to be of equal length) project equally from the surface of the sun g. The end of the arm e2 supports one (the south) pole of the earth. The bent end of the arm c1 supports the opposite pole. lThe arm c2 contains a revolving disk, c3, to which is attached, at a distance from its center corresponding to the action of the cams al a2, the arm c1 by a screw-pin running through a slot in the arm; and now (look at Fig. 3) supposing the earth to be at one of the equinoxes and its axis to be parallel to the axis of the heavens, the action of the whole device, as the thumb-piece y is rotated, is to keep the two poles of the earth parallel to themselves at all times. By this device, also, the disk cis made to revolve backward, causing the north pole of the earth to describe a small ellipse in a backward direction from its direct motion, thus representing the earths nutation.

It will be observed that in the course of a' revolution the arms will reach two points familiarly known as dead-centers, and this mechanical difficulty it is necessary to overcome. It is done (see Fig. 5) by a cam, '02, fastened to the axis of the revolving disk c3,

upon the back sideso to speak-of the disk,'

which, just before it gets to these centers, presses against the at spring e2, which spring is fastened to the back side of the arm c2, and presses by the spring, and immediately after the end of the cam presses by the spring will throw it past the center. There is a thin round collar in the arm c2 which encircles the revolving,disk c3, and to the back side of this collar the thin round plate c"I is fastened, a hole through the center of which serves as a bearing for the axis of the revolving disk c3, and it is on the back side of this' plate c7 that the cam a2 revolves. The line 02 indicates the milky-way. The small plate marked 1()07 represents the asteroids. The arm m2, which carries the moon, is attached to the bent end of the arm c1 at such a place and in such a manner as to show the eccentric and peculiar orbit of the moon about the earth. The circumference of the disks@ is divided into thirtyseven (37) equal parts to denote the semi-annual falling back of the moons nodes.

Claims.

l. In combination with the stationary rings a b t, representing the celestial equator, meridian, and eeliptic, the movable frame e w, representin g the perpetual celestial equator and meridian revolving around the ecliptical axis t'.

2. The whole shaft composed of' the axis i, axis h, and the axis It, arranged relatively to each other at the proper angles of variation,

for the purpose set forth.

3. The combination of the shaft, as described in the immediately preceding claim, with the ring c, turning in the same and having the bearings at the poles of the ecliptic i i', substantially as and for the purpose set forth.

4L. The combination of the shaft p, disk x, the nut z, and the disks s s s s s s s s s, supporting the planets and asteroids, substantially as and for the purposes set forth.

5. The combination of the arms c1 c2, revolving disk c3, cam c2, and spring c2, constructed substantially as and for the purposes set forth.

6. The combination of the shaft p', thumbpiece y, disk x, cams al a?, and arms cl c2, constructed substantially as and for the purposes set forth.

HENRY BRYANT.

VVitn esses WM. E. SIMoNDs, E. B. FARNHAM. 

